The present technology relates to a projection apparatus performing a video display.
There has recently developed an LCD (Liquid Crystal Display) projector adopting the 3D (three-dimensional) active shutter technology.
The active shutter technology belongs to the video display technology with which sense of depth is created. With such an active shutter technology, stereoscopic viewing is achieved with parallax, which is created by alternately displaying a left-eye picture and a right-eye picture, and in synchronization with switching of the pictures, by alternately blocking the user's right and left eyes view of 3D glasses.
The issue here is that such a projector projecting 3D images as described above has a difficulty in quality control compared with a projector projecting 2D (two-dimensional) images. This is because, as for light polarized after reflection on a screen, the 3D glasses pass therethrough only components polarized in a specific direction, and this polarization state greatly affects the quality of the 3D images, i.e., causes color unevenness, and reduction of brightness.
With 2D images, the 3D glasses are not used, and thus the image quality is not affected by the polarization state of light after reflection on the screen because the light is directed into user's eyes uniformly irrespective of the polarization state. On the other hand, with an LCD projector or others adopting the 3D active shutter technology, an important factor is to give consideration to the polarization state of light before the light reaches the 3D glasses.
As a previous technology, proposed is a projection display apparatus that makes uniform the amount of RGB (Red, Green, and Blue) light in the horizontal/vertical directions, and changes the polarization state of each of the color light. As an example, see Japanese Patent Application Laid-open No. 2007-304607.